The present invention relates to the removal of molds, central and/or peripheral mold parts from a casting.
The shaping of parts by means of molds and forming of metal castings by means of molds is a technique of long (even ambient) standing. Herein the liquified material such as molten metal is poured into a mold being so to speak a negative of the contour of the part to be made. Subsequently the molten metal is permitted to solidify in the mold. Such a mold is usually made of ceramic material. Following the solidification and cooling the mold is simply broken off in one form or another and the casting part is cleaned by means of water jets, sand blasting, chemically or otherwise so as to obtain complete removal of any mold material parts or particles from the casting.
If the shape of the casting is of a simple nature the mold removal process is commensurately simple. However, in the case of a complex contour, particularly where the casting has corners, pocketlike contours, indents or the like, the possibility cannot be excluded that certain parts of the mold still remain with the casting. This in turn may detrimentally affect the use life of the cast product.
A number of methods and devices for removing molds or mold parts or cores from a casting are known, for example through the German printed patent application No. 19 62 182; the German journal Giessereitechnik, Vol. 29, 1983, issue 3, pages 205-210 or pages 239-244; also a book known under the name "Giesserei-Lexikon", 1983, page 859 refers to such methods and equipment. Particularly these methods involve removal of mold parts from the casting through arc discharge or explosion producing shock waves or ultrasonic waves may be used for that removal.
These methods of the prior art are on the other hand usable only when the parts i.e. the castings are still relatively simple. It is still not guaranteed that mold parts which lodge in indents, bores, undercut portions or the like will in fact be removed so that the problem mentioned above, namely the reduction in use life of the casting on account of residual mold parts is still not solved.